1. Field of the Invention
The present invention relates to a storage apparatus having more than one round-shaped storage area. The invention particularly relates to a storage apparatus having a recording medium such as hard discs and a computer-readable recording medium whose storage areas can be easily recognized.
2. Description of the Related Art
FIG. 13 shows a previous magnetic storage apparatus in schematic form. The magnetic storage apparatus 100 has more than one circular magnetic disc 110 fixed to a spindle 130 of a SPM (Spindle Motor) at their centers (a center of rotation).
The magnetic disc 110 is a platter on which a magnetic recording layer is formed, and such a recording layer is provided on either side or both sides of the platters. The magnetic head 120 writes information on the surface (storage area) of the magnetic discs 110 and it also reads-out information recorded thereon.
The magnetic storage apparatus 100 has magnetic heads 120 provided one for each surface of the magnetic discs. A specific magnetic head 120 accesses a specific surface of a specific magnetic disc 110 to write/read data thereto/therefrom. The magnetic heads 120 are selected (head switching) as required to select a storage area to access.
When switching the magnetic heads 120, the magnetic storage apparatus 100 identifies which one of the storage are as the magnetic head 120 is currently accessing, to confirm that an intended proper magnetic head 120 is selected.
Generally speaking, the magnetic storage apparatus 100 is normally equipped with eight magnetic heads 120 at most. Therefore, numbers of “0” through “7” (in decimal number system) are represented in binary form (“000” through “111”), and these 3-bit information items are stored, one in each storage area of the magnetic discs 110, as information that identifies an individual magnetic head 120 (storage area)
FIG. 14 shows a magnetic disc, in schematic form, equipped to a previous magnetic storage apparatus. On the magnetic disc 110 of FIG. 14, there are provided servo frames 111 arranged at regular intervals in a radial manner, which servo frames 111 store information identifying the magnetic head 120.
For instance, the foregoing 3-bit information is stored in one of the servo frames 111 provided on the storage area. Alternatively, the three bits of the information can be separately stored, one in each of the servo frames 111 adjacent to each other. Such information is used to recognize the head numbers given to the magnetic heads 120. The magnetic head 120 reads-out this information to evaluate whether or not an intended head has been selected.
In addition, the magnetic storage apparatus 100 needs to detect where on the magnetic disc 110 the magnetic head 120 locates. In a previous magnetic storage apparatus 100, the magnetic head (not shown) reads-out index signals recorded in servo frames 111, and referring to the index signals, it is detected where on the magnetic disc 110 the magnetic head 120 locates.
For example, an index signal can be recorded in one of the servo frames 111 provided on a storage area, or alternatively, positioning information can be recorded in all the servo frames 111, so that the magnetic head 120 reads-out such information, thereby detecting where on the magnetic disc 110 the magnetic head 120 locates.
[Patent Document 1]
Japanese Patent Application Laid Open NO. HEI 11-3574 (FIG. 1)
[Patent Document 2]
Japanese Patent Application Laid Open NO. HEI 4-337566 (Pages 2 to 3)
However, the above-mentioned conventional magnetic storage apparatus 100 has the following problem relating to the methods for recording information identifying the magnetic head 120, that is, the method in which only one of the servo frames 111 on the storage area stores information (3-bit information) identifying the head number of the magnetic head 120, and the method in which the three bits of the information are separately stored, one in each of the servo frames 111 adjacent to each other. Since such information is read by the magnetic head 120, the apparatus must sometimes wait until the desired frames rotate to the magnetic head 120, thereby causing rotational delay time as long as one disc rotation at the maximum.
When detecting an index signal, the method in which only one of the servo frames 111 on the storage area stores information (3-bit information) identifying the head number of the magnetic head 120 has the following problem: since the index signal is read by the magnetic head 120, the device must sometimes wait until the desired frames rotate to the magnetic head 120, thereby causing rotational delay time as long as one disc rotation at the maximum. Additionally, if the index signal is defective due to any reasons, it cannot be read out, so that positioning control of the magnetic head 120 is unavailable.
Further, the method in which positioning information is recorded in all the servo frames 111 has the following problem: servo frame length is increased, thereby affecting efficient use of the magnetic disc 110. In a case where 256 servo frames 111 are formed on a storage area (magnetic disc 110), for example, at least eight bits (28=256) need to be prepared in each servo frame 111 for storing the positioning information.